The second thing my acquaintances who enlisted cited was retiring from military with half pay after 20 years of service and access to veterans’ benefits which in hindsight looks pretty nice for most non professional career options otherwise.

It's not a bad deal, especially when you consider you could live with minimal expenses while in the military. Saving a lot is not hard even on modest military pay when your living costs are all covered. I can't think of any other opportunities where you could start working at 18, save a lot, retire at 38, and get a pension.

Living costs, food costs, most of your clothing, transportation, etc. You literally just pay for fun and off duty extra activities / extra food.